In an automobile, the thickness of thereof was showing a tendency to thin out by reduction of weight and the progress of strength of the steel plate. Therefore, from the request that the prevention of a dent of the body of the automobile, and from the request of a diminution of the noise when a door shuts, a material for reinforcement of the steel plate was stacked for said steel plate.
Examples of said material for reinforcement of the steel plate include a material which a restricted layer such as aluminum foil or a glass cloth etc. puts up a bark of thermosetting foam viscoelasticity layer manufactured by epoxy resin or a rubber etc.
Said restricted layer may be used for reasons of endowing the performance of toughness for the thermosetting foamed viscoelasticity layer.
As said material for reinforcement of the steel plate, two layers structure composed of said restricted layer and said thermosetting foam viscoelasticity layer is to be desired for reasons of price-respect etc. However, in former example, it is often necessary at least three structure, because of the need of compatibility both the performance of vibration-damping and the performance of reinforcement (Japan Unexamined Patent Publication No. Hei. 7-68696, Japan Unexamined Patent Publication No. Hei. 2005-186303, Japan Unexamined Patent Publication No. Hei. 8-35538).
Said material for reinforcement of the steel plate become as higher an effect of reinforcement as increase a degree of hardening of said thermosetting foam viscoelasticity layer, on the other hand, an effect of the diminution of the noise when the door shuts and rainy sound become lose. Also, when if a structure of the only a vibration-damping material, an effect of vibration-damping become higher, on the other hand, the effect of reinforcement become extremely low. According as kind of the automobile, there is a case that both the steel plate reinforcement sheet and the vibration-damping sheet are used for one plate of door. In this case, it is preferred to have both the function of reinforcement and the function of vibration-damping, generally, but it is extremely difficult to have both these function of reinforcement and vibration-damping.
The automobile has a vertical section and a rear section such as the door, a quarter and a roof. As above mentioned, it is necessary to stick the material for reinforcement of the steel plate on the vertical section such as the door. On the other hand, at the rear section such as the roof too, the structure of the material for reinforcement of the steel plate is carried out, for example, from the request of both said reinforcement and vibration-damping that the prevention of the dent when washing etc., the measures of rainy sound and the measures of propagation of sound to automobile-body. Said material for reinforcement of the steel plate was used the foam-type thereof, but, in order to structure against said rear section, it is necessary excellent heat resistance and adhesive strength more than structure against said vertical section such as the door.
However, said foam-type material for reinforcement of the steel plate has inconvenience by drop-out etc., in a roof-panel of the ceiling, generally, therefore, it is numerous toward to select non-foam-type thereof.
In order to stick the material for reinforcement of the steel plate on the automobile, foaming and heat-melting-adhesion by utilization of heat (energy) of a heating apparatus (heating drying oven) in coating and drying line of thereof are effective. In the automobile production line, various coating work process thereof is carried out after through the process composed of washing treatment of an antirust oil from the face of the steel plate, chemical conversion treatment and electrodeposition. Then, in order to stick the material for reinforcement of the steel plate on the back side of an outside section, it need to stick before a stage of structure of the body, it is desirable to stick before or after washing and removing-oil treatment. Therefore, generally, in the case of before-after electrodeposition, at ratio of near 100%, it carried out before electrodeposition, in the present circumstances. Whereas, in case of structure of a member such as the material for reinforcement of the steel plate on the above-mentioned ceiling, in order to try equation of the force of pressure-fixation, the structure by an automatic machine for pressure-fixation is desirable. But the establishment of said automatic machine is difficult before electrodeposition for reason of relation of space in the line of the automobile, then said establishment carries out after electrodeposition. From said request, the material for reinforcement of the steel plate of the type which may be structured also after electrodeposition was proposed partially. But, temperature-difference of structure between before electrodeposition and after electrodeposition is 30° C. or so, it is need to make a prescription of low-temperature-hardening as the material for reinforcement of the steel plate of the type which may be structured also after electrodeposition. However, in this case, said material against low temperature has trouble of storage stability when temperature was rose, when said material uses as composition elements of the material for reinforcement of the steel plate after preservation of proper period, said material has trouble of deterioration of the performance of impact resistance.
In the material for reinforcement of the steel plate, a pigment having high aspect ratio such as mica and special denatured asphalt may be added for reason of respect of cost and intensity, but the addition of said pigment having high aspect ratio such as mica and special denatured asphalt has troubles that initial baking performance is good for the rear section such as the ceiling etc., however, in the result of the test of the performance of impact resistance, when the impact from the outer side was added, the appearance of float part and peel part are occurred, it can not show fully function of reinforcement and vibration-damping, also, after preservation of proper period, said material has trouble of deterioration of the performance of impact resistance.    Patent Documents 1: Japan Unexamined Patent Publication No. Hei. 7-68696, Japan Unexamined Patent Publication No. 2005-186303, Japan Unexamined Patent Publication No. Hei. 8-35538